10,000 years ago, at a time when humans recorded historical events by telling mythical stories that got passed from one generation to the next, huge parts of the North American continent were deluged by massive walls of water. They were, as geologist David R. Montgomery writes in this month's Discover magazine, "Biblical-type floods." Huge regions of the Pacific Northwest, called the "scablands" were chewed up by flash floods that were more like tsunamis. And it was all caused by the melting of the glaciers from the last ice age. As the walls of ice damming lakes melted away, the waters would rush out across the land.

Here's a map of the ice age floods (the gray regions are flood areas) — click to enlarge.

Advertisement

Though it took nearly a century for geologists to recognize the deep scores in the earth, displaced boulders, and deep ripple marks on the prairies as signs of what is today called the Missoula Flood, apparently many tribes local to the Pacific Northwest had very similar stories about floods. Writes Montgomery:

There is now compelling evidence for many gigantic ancient floods where glacial ice dams failed time and again: At the end of the last glaciation, some 10,000 years ago, giant ice-dammed lakes in Eurasia and North America repeatedly produced huge floods. In Siberia, rivers spilled over drainage divides and changed their courses. England's fate as an island was sealed by erosion from glacial floods that carved the English Channel. These were not global deluges as described in the Genesis story of Noah, but were more focused catastrophic floods taking place throughout the world. They likely inspired stories like Noah's in many cultures, passed down through generations.

Since devastating floods were a fact of life on the margins of the world's great ice sheets, people in those areas probably witnessed them. Early missionaries in eastern Washington reported stories of a great flood among Yakima and Spokane tribes, who could identify locations where survivors sought refuge. An Ojibwa Indian legend from around Lake Superior tells of a great snow that fell one September at the beginning of time: A bag contained the sun's heat until a mouse nibbled a hole in it. The warmth spilled over, melting the snow and producing a flood that rose above the tops of the highest pines. Everyone drowned except for an old man who drifted about in his canoe rescuing animals. The native inhabitants of the Willamette Valley told stories of a time the valley filled with water, forcing everyone to flee up a mountain before the waters receded.

This is fascinating stuff, and does hint at the idea that some flood myths could be the neolithic equivalent of historical documentation. Read more of Montgomery's story at Discover to find out where you can see the evidence for these floods, and how scientists discovered them.